Our Spare Room/Future Nursery

I have been putting ideas away for our nursery for a few weeks now and trying to figure out how to transform this:

Apollo says Hi!

Into something more adorable and child friendly. Please ignore the hideous blue carpets - those will be replaced with something more neutral in the coming months.

I have a few things that I really like - for a boy I adore this set:

We're leaning towards getting dark wood furniture so I'm not really sure if this will work or not with that. We also won't have half white-half some other color wall - it'll be all one color but I'm not sure what color yet.

For a girl I'm a little torn because there are three sets that I really like, first this one:

I think it's adorable and it matches fantastically with the dark wood furniture we're thinking about. I doubt I'll paint the tree thing but I'll give it a shot first. Unless, of course, I can find a wall decal.

Then there are these 2 sets that my friend K found for me:

All are equally adorable for a girl. I wouldn't do a pink wall though - I generally dislike pink but it can be done tastefully. We'd emphasize the green or yellow in here to tone down the pink. But I can't decide which I like the best because they are all fantastic.

This is about as far as I've gotten on decorating our nursery for our hypothetical child. I haven't bought anything yet because well, that would be dumb and further fuel my baby fever. Also it doesn't make any sense to buy anything until we know if we are having a boy or a girl and we can't find that out until I'm well into a pregnancy. So obviously I need to get pregnant first.

So any ideas or suggestions for how to turn that ugly room into something adorable?